docs: def extract_agg_damages(dstore, what):
      """
      Aggregate damages of the given loss type and tags. Use it as
      /extract/agg_damages/structural?taxonomy=RC&zipcode=20126
  
      :returns:
          array of shape (R, D), being R the number of realizations and D the
          number of damage states, or an array of length 0 if there is no data
          for the given tags
      """
      loss_type, tags = get_loss_type_tags(what)
      if 'dmg_by_asset' in dstore:  # scenario_damage
          lti = dstore['oqparam'].lti[loss_type]
          losses = dstore['dmg_by_asset'][:, :, lti, 0]
      else:
          raise KeyError('No damages found in %s' % dstore)
      return _filter_agg(dstore['assetcol'], losses, tags)